• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.18-24
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• 1999

ThisPaper investigates the feasibility of using acoustic emission signal analysis for the detection of built-up edge during machining. Experiments were conducted on a CNC-lathe using conventional carbide insert tools under various cutting conditions. The cutting forces were also measured for comparisons. Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. It is shown that under conditions in which a built-up edge is generated, the variation of $AE_{rms}$ signal with cutting speed can be quite different from the generally accepted linear, monotonic increase as previously reported. The feasibility of utilizing $AE_{rms}$ in built-up edge sensing is suggested.

• 전자공학회논문지B
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• 제29B권9호
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• pp.1-7
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• 1992

This paper proposes a built-in self-test tchnique for CMOS circuits. To detect a stuck-open fault in CMOS circuits, two consequent test patterns is required. The ordered pairs of test patterns for stuck-open faults are generated by feedback shift registers of extended length. A nonlinear feedback shift register is designed by the merging method and reordering algorithms of test patterns proposed in this paper. And a new multifunctional BILBO (Built-In Logic Block Observer) is designed to perform both test pattern generation and signature analysis efficiently.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.51-52
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• 2007

Built-in voltage in organic light-emitting diodes was studied using modulated photocurrent technique ambient conditions. From the bias voltage-dependent photocurrent, built-in voltage of the device is determined. The applied bias voltage when the magnitude of modulated photo current is zero corresponds to a built-in voltage. Built-in voltage in the device is generated due to a difference of work function of the anode and cathode. A device was made with a structure of anode/$Alq_3$/cathode to study a built-in voltage. ITO and ITO/PEDOT:PSS were used as an anode, and Al and LiF/AI were used as a cathode. It was found that an incorporation of PEDOT:PSS layer between the ITO and $Alq_3$ increases a built-in voltage by about 0.4V. This is consistent to a difference of a highest occupied energy states of ITO and PEDOT:PSS. This implies that a use of PEDOT:PSS layer in anode improves the efficiency of the device because of a lowering of anode barrier height. With a use bilayer cathode system LiF/Al, it was found that the built-in voltage increases as the LiF layer thickness increases in the thickness range of 0~1nm. For 1nm thick LiF layer, there is a lowering of electron barrier by about 0.2eV with respect to an Al-only device. It indicates that a very thin alkaline metal compound LiF lowers an electron barrier height.

• 전자공학회논문지
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• 제50권6호
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• pp.122-130
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• 2013

메모리반도체산업이 성장함에 따라 수요와 공급이 큰 폭으로 증가하고 있다. 그 중 플래시 메모리가 스마트폰, 테블릿PC, SoC(System on Chip)산업에 많이 사용되고 있다. 플래시 메모리는 NOR-형 플래시 메모리와 NAND-형 플래시 메모리로 나뉜다. NOR-형 플래시 메모리는 BIST(Built-In Self Test), BISR(Built-In Self Repair), BIRA(Built-In Redundancy Analysis) 등 많은 연구가 진행되었지만 NAND-형 플래시 메모리 BIST는 연구가 진행되지 않았다. 현재 NAND-형 플래시 메모리 패턴 테스트는 고가의 외부 테스트 장비를 사용하여 테스트를 수행하고 있다. NAND-형 플래시 메모리에서는 블록단위로 소거, 페이지 단위로 읽기, 쓰기 동작이 가능하기 때문에 자체 내장 테스트가 존재하지 않고 외부장비에 의존하고 있다. 고가의 외부 패턴 테스트 장비에 의존해서 테스트를 수행하던 NAND-형 플래시 메모리를 외부 패턴 테스트 장비 없이 패턴 테스트를 수행할 수 있도록 두 가지의 유한 상태 머신 기반 구조를 갖고 있는 BIST를 제안한다.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.398-404
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• 1999

The EGR is needed for one of various strategies to reduce NOx emission. But to get the proper EGR rate the intake and exhaust system become complicated. That is a reason why we consider using the built0in EGR system. The built-in EGR is a system which reduces Nox by controling the residual gas fraction in cylinder by changing valve timing and valve lift of intake and exhaust. In this paper characteristics of volumetric efficiency and residual gas fraction in cylinder were investigated for various engine speeds by changing valve timing and valve lift of intake and exhaust. In this paper characteristics of volumetric efficiency and residual gas fraction in cylinder were investigated for various engine speeds by changing valve timing and valve lift of intake and exhaust in the 4 stroke-cycle diesel engine. Volumetric efficiency and residual gas fraction were calculated by the method of characteristics. As the results the possibility of suing the built-in EGR system was confirmed.

• Mycobiology
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• 제47권4호
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• pp.430-440
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• 2019

Fungal contamination of built-in furniture is a frequent problem in Korea when new apartment is built. However, domestic information on the contaminating fungi is very limited. This study was conducted to isolate, identify and characterize the fungi of the problem in one of the apartment houses where the fungi were claimed in the built-in furniture before the house owner moves in. Fungi present in the furniture installed in a main room, dress room, and kitchen side were visually and microscopically confirmed and purely isolated on PDA. The isolated fungi were identified by analyzing the morphological characteristics and nucleotide sequence of the ITS, calmodulin gene, and TEF-1α gene. Aspergillus creber, A. niger, A. pseudoglacus, A. ruber, Cladosporium perangustum and Penicillium commune were identified. Four out of the six fungal species were positive for at least one enzyme in six kinds of extracellular enzyme assays. When these four species (A. creber, A. niger, C. perangustum and P. commune) were inoculated onto four kinds of wood chips of furniture materials, they were able to colonize all of the wood chips. Their settlement was better at 95% humidity condition than at 30% humidity condition. Among the four species, C. perangustum caused the darkest discoloration and secreted the most number of extracellular enzymes. The four species were re-isolated from the colonized wood chips and confirmed as the problematic fungi in the built-in furniture.

• 한국건축친환경설비학회 논문집
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• 제12권6호
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• pp.567-578
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• 2018

The purpose of this study was to evaluate condensation prevention for condensation vulnerable areas around built-in furniture of apartment buildings by applying auxiliary heating device. Recently, the condensation and mold problems of apartment buildings has been growing due to high insulation and high air-tightness performance for energy saving. Condensation at built-in furniture were generally found in winter at the of furniture's back panels, adjacent surfaces of wall, floor and ceiling. These problems are related to the weather conditions and indoor room conditions in winter. To solve these problems, auxiliary heating device was developed and could be installed. The aim of paper is to analyze the thermal environment around the built-in furniture which were applied and not applied auxiliary heating device in winter. In results, it was possible to increase the surface temperature of vulnerable areas around built-in furniture by applying auxiliary heating device, and to minimize condensation problems by using the minimum device.

• Steel and Composite Structures
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• 제33권1호
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• pp.37-66
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• 2019

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless-steel lipped channels as compression members are becoming increasingly popular. The advantages of using stainless-steel as structural members are corrosion resistance and durability, compared with carbon steel. The AISI/ASCE Standard, SEI/ASCE-8-02 and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element analyses have been reported in the literature for such back-to back cold-formed stainless-steel channels. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (gAS/NZS) standards for built-up carbon steel sections only describe a modified slenderness approach, to consider the spacing of the intermediate fasteners. Thus, this paper presents a numerical investigation on the behavior of back-to-back cold-formed stainless-steel built-up lipped channels. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404 have been considered. Effect of screw spacing on the axial strength of such built-up channels was investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns, failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines by AISI and AS/NZS. In total, 647 finite element models were analyzed. From the results of the parametric study, it was found that the AISI & AS/NZS are conservative by around 10 to 20% for cold-formed stainless-steel built-up lipped channels failed through overall buckling, irrespective of the stainless-steel grades. However, the AISI and AS/NZS can be un-conservative by around 6% for all three grades of stainless-steel built-up channels, which failed by local buckling.

• 한국정보통신학회논문지
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• 제9권5호
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• pp.1089-1095
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• 2005

본 논문에서는 5GHz 저잡음 증폭기(LNA)의 성능 측정을 위한 새로운 형태의 저가 BIST(Built-In Self-Test) 회로를 제안한다 이러한 BIST 회로는 system-on-chip (SoC) 송수신 환경에 적용될 수 있도록 설계되어 있다. 본 논문에서 제안하는 BIST 회로는 입력 임피던스, 전압이득, 잡음지수, 입력반사손실(input return loss) 및 출력 신호 대 잡음전력비(signal-to-noise ratio)와 같은 저잡음 증폭기의 주요 성능 지수를 측정 할 수 있으며, 단일 칩 위에 제작되어 있다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.230-236
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• 2001

We developed a built-in sensor bearing to measure the rotor motion of a rolling piston type compressor for the air conditioner. Because of needs for the high efficiency and long life span of compressor, and the usage of alternative refrigerants, the operating condition of the compressor becomes more severe. The accurate measurement of the rotor motion of the compressor can contribute greatly to the design and analysis of the hydrodynamic bearing. However, it is difficult to measure accurately the shaft behavior of small compressor because of the small space for the sensor mount, high temperature and pressure of compressor, oil mixed with refrigerant, and electromagnetic noise of the motor. To overcome these difficulties, we develop the cylindrical capacitive sensor that is built in the hydrodynamic bearing and calibrate the built-in sensor bearing indirectly through measuring the oil relative permittivity. We measured the rotor motion as well as suction and discharge pressures in various conditions. The several experimental results show that the developed built-in sensor bearing can measure the rotor motion not only in steady state but also in transient state.